1. Field of the Invention
The present invention relates generally to a electric motor driven switch machine for switching railroad tracks so that trains may switch from one track to another. More particularly, the present invention relates to an electric motor driven switch machine having a ratchet mechanism on a hand throw means.
2. Description of the Prior Art
It is a requirement for operation of a railroad network to have the capability of switching trains from one track to another. A common method of providing this switching capability is to install an electric motor driven switch machine along side of, and interconnected to, a switch point of a railroad track. These switch machines often have one or more manual operations for shifting the position of the track without the use of the electric motor for certain situations, such as when electric power is not available, or when installation or maintenance action is required.
Two manual operations typically available within switch machines are the hand crank and hand throw operations. The hand crank operation permits operational personnel to switch the track at the switch point by turning a hand crank for maintenance and installation purposes. The hand throw operation permits operational personnel to switch the track, i.e., throw the switch machine, at the switch machine when control signals from a remote facility are not able or not desired to reach the switch machine.
The hand throw operation is performed by controlling a hand throw means that is positioned on the side of the switch machine away from the corresponding railway tracks. This is a safety requirement for operational personnel in order to distance them away from moving rail equipment. Since a switch machine is adaptable for installation on either side of the tracks, depending on installation requirements, the hand throw means must be capable of being removed and installed on either side of the switch machine.
Traditional hand throw devices have hand throw arms that operably rotate 180 degrees. A latch stand at both sides of the hand throw shaft is used to secure the hand throw arm when a hand throw operation has been completed. The hand throw arm is secured to the latch stand with a pad lock to prevent unauthorized use of the hand throw means. The pad lock also provides a reliable indication to accident investigators of the position of the hand throw arm after an accident.
The hand throw means currently used also provides a mode selector device that enables operational personnel to select between a power mode and a hand throw mode for the switch machine. When the power mode is selected, a hand throw operation is not possible. This is a personnel safety feature that prevents a remote operator from energizing the electric motor and operating the switch machine when the hand throw operation is desired. The mode selector device is also secured and locked in the latch stand along with the hand throw arm.
Since existing switch machines with hand throw capabilities require 180 degrees of handle rotation to complete a throw, and the switch machines are typically installed at or near ground level, an operator must lift the hand throw arm upward and then push it over and down to the opposite position. This operation results in stress and strain on the operator's back, spine, joints, muscles and other parts of the body that must exert considerable force in an awkward position without any mechanical aid from the hand throw means.
Lower back injury and the resulting medical treatments, lost labor time and cost of additional personnel have steadily mounted over the years and have become a significant factor in the rising cost of operating a railroad, not to mention the pain and suffering imposed on personnel.
Accordingly, it is a primary object of the present invention to overcome the aforenoted disadvantages associated with the designs of prior art hand throw means by reducing or eliminating the strain required for its operation and reducing the time required to install and maintain the hand throw means, while retaining all of the desired features available in existing hand throw mechanisms.
It is another object of the present invention to provide a self-contained module that contains all machine elements required to perform the hand throw operation, such that the module can be easily bolted to a switch machine when the switch machine is being assembled or after it is installed near railway tracks.
It is still another object of the present invention to provide a module that can be readily repositioned from one side of the switch machine to the other and adjusting its hand throw and to accommodate operation from the new position.
It is yet another object of the present invention to provide a module that contains a gear system having a 2 to 1 mechanical advantage in favor of the hand throw operator.
It is still yet another object of the present invention to provide a ratchet mechanism that permits an operator to raise the hand throw arm to approximately the vertical position before the application of force to the hand throw arm is required.
It is a further object of the present invention to provide a hand throw means that permits an operator to position herself or himself in a favorable position for the application of force without excessive stress and strain to her and his body.
It is a yet further object of the present invention to provide a direction selector for the ratchet mechanism that permits torque to be applied in either a clockwise or counter-clockwise direction as desired by the operator.
It is a still further object of the present invention to provide a hand throw means that permits the use of a hand throw mode selector lever for selecting between a hand mode and a power mode selector lever.
It is a still yet further object of the present invention to provide a hand throw means having a hand throw arm that can be returned to a latch stand and secured with a pad lock at the completion of its operation.